Ok i did my rear brakes today. My son in law came out and asked if he could help i said sure put a little brake fluid in . He did and it was dot 5. After he put a capful in he told me the fluid he put in was purple and the fliid in the master cylinder was not it was a dark clear. Its my fault for not checking. But the cover said dot 5 so i assumed it was dot in it . My question will only a cap full cause me problems.? Or should i remove all the fluid out of the resivior. I have not used the rear brake peddel at all.

From Wikipedia
DOT 5 is a silicone-based brake fluid (contains at least 70% by weight of a diorgano polysiloxane[1]).

Unlike polyethylene glycol based fluids, it is hydrophobic. Its chief advantage over other forms of brake fluid is that silicone exhibits a more stable viscosity index in extreme temperatures. It is widely used in the antique automobile arena as well as it does not damage paint.

Using DOT 5 in a DOT 3 or DOT 4 system without proper flushing will cause damage to the seals and cause brake failure. DOT 5 brake fluid is not compatible with anti-lock brake systems. DOT 5 brake fluid absorbs a small amount of air requiring care when bleeding the system of air.

If the cover says Dot5, it was most likely Dot5 in there already. It just loses it's color and gets nasty looking with age. A little fresh stuff in there won't hurt, but it's a good idea to just flush the system if it doesn't look clean and purple. Especially if you haven't done it before and you have any doubts about what was in there.

If the cover says Dot5, it was most likely Dot5 in there already. It just loses it's color and gets nasty looking with age. A little fresh stuff in there won't hurt, but it's a good idea to just flush the system if it doesn't look clean and purple. Especially if you haven't done it before and you have any doubts about what was in there.

You can flush the system quick and easy with a DIY pressure bleeder. The real deal by Max isn't being sold here anymore, but you can build your own for about $30 with stuff from Home Depot.
Here's a link to what I'm talking about.www.1130cc.com/forums/showthread.php?t=42544
Does anyone know what happened to Max's video that shows it in action?

If it has never been done than the oil was dot 4. That is what was put in at the factory. Referring back to my other post Dot4 and dot5 are not compatible with each other. Dot 4 is a polyethylene glycol based fluid. Dot 5 is a silicone-based fluid. The only other difference is the boiling point.

If it has never been done than the oil was dot 4. That is what was put in at the factory. Referring back to my other post Dot4 and dot5 are not compatible with each other. Dot 4 is a polyethylene glycol based fluid. Dot 5 is a silicone-based fluid. The only other difference is the boiling point.

The factory used Dot 5 in the early bikes, I'm not sure exactly when they changed to Dot 4 but my 2003 requires Dot 5.

Mike

__________________It's not how fast you go, it's how fast you get there!

They switched to DOT 4 with the Brembo braked bikes.
DOT 5 as other types will yellow or brown as it ages, it was explained once to me as being like poop, it all goes in different colors but all comes out brown. If yours looks that way it just needs flushing. Do it and you'll appreciate the improvement.

If it has never been done than the oil was dot 4. That is what was put in at the factory. Referring back to my other post Dot4 and dot5 are not compatible with each other. Dot 4 is a polyethylene glycol based fluid. Dot 5 is a silicone-based fluid. The only other difference is the boiling point.

Um, not to argue, but my '02 came from the factory with DOT-5 in the brakes and clutch. I've since changed the fluid, staying with DOT-5, and have had no issues with the brakes, or clutch.